A. Field of the Invention
The present invention relates to a method and apparatus for removing a blood clot from a vessel.
B. Description of the Prior Art
Venous thrombosis is the term used to describe a blood clot (thrombus) in a vein of the body. Most commonly these thrombi are found in the veins of the lower extremities; the thighs and calves. Thrombi found in veins deep in thighs or calves give rise to a condition called "deep vein thrombosis" (DVT). Venous thrombosis can occur in healthy as well as sick individuals.
A complication most commonly associated with venous thrombosis is the condition known as "pulmonary embolism." A pulmonary embolus is actually a clot that has broken free from a vein wall and has traveled to the pulmonary artery, then, if not removed, to a lung, causing blockage in an artery of that lung. When an embolus blocks a blood vessel in the lung, breathing is compromised and death may ensue.
It is estimated that in the United States each year, there are approximately 50,000 deaths resulting from pulmonary embolism. For this reason, pulmonary emboli must be removed from the pulmonary artery.
Many catheter systems are designed for percutaneous fragmentation of large pulmonary emboli. The devices generally consist of an impeller rotating at high speed at the end of the catheter for fragmentation of the clot While the developers of these apparatus often boast of quick and thorough fragmentation, particles in the effluent larger than 10 microns account for about 9% of the treated embolus weight. Such particles, once dislodged, may move into the lung and cause serious problems. Moreover, these catheter systems carry natural risks of damage to a vessel wall by the rotating impeller.
An apparatus and method are therefore needed to remove clots from blood vessels without rotating blades or fragmentation.